Exclusively BF/AF/ovulation question

Ya ya I know this has been asked before but.. I couldn't get a
definitive answer. I exclusively bf my 4.5 month old dd (not quite, I
pump during the day but I figure it's the same). Having said that, who
is it that visits me one day a month and scares the heck out of me
because I'm not wearing a pad? Is it Auntie Flo or Cousin Marie or
someone else?

I know it's about that time to get my period back. But these flows
really don't come with cramps, don't follow any date not that I've
been counting.
Does this mean I'm ovulating?
When will the periods become consistent and last 3-4 days like they
used to do?
Can the periods go away for couple of months and become kinda
irregular with bf?
I know this is a big time YMMV thing but all I'm asking is for your
opinions and experiences.

Thanks.